Nitrogen and Potassium Fertilization Information

December 2008, Drs Mulvaney and Khan of the University of Illinois presented at our Growers Sales meeting. They spoke about experiments showing the ineffectiveness of past university methods of determining rates of fertilization. Below are some articles our readers may appreciate.

By R.L. Mulvaney, S.A. Khan, T.R. Ellsworth. CSA News March 2006. Examination of the proven-yield (PY) method of N recommendations. Per Dr. Mulvaney: "It was disturbing to see how poorly this method performed...In fact, on average, the error itself was greater than the economically optimum N rate."

By S.A. Khan, R.L. Mulvaney, T.R. Ellsworth and C.W. Boast. CSA News December 2007. After analyzing soil profile samples from the historic Morrow Plots and studying published research covering more than 100 years, the authors found consistent evidence of an organic carbon decline for fertilized soils. "Inorganic nitrogen has long been known to promote decomposition of carbonaceous residues..." explains Richard Mulvaney.